1. Field of the Invention
The present invention relates to an optical transmission module.
2. Description of the Related Art
JP 2013-148825 A discloses an optical module.
An optical transmission module that converts an electric signal to an optical signal and outputs the optical signal is provided with a light-receiving element for monitoring light emitted from a light-emitting element. The light-receiving element monitors a light output emitted from the light-emitting element, and the optical transmission module controls, based on the monitoring result, the intensity of the light emitted from the light-emitting element so as to be constant.
It is considered that an optical transmission module provided with a plurality of light-emitting elements is preferably provided with as many light-receiving elements as the light-emitting elements for monitoring light outputs emitted from the light-emitting elements.
Because of the demand for the miniaturization of the optical transmission module in recent years, when the plurality of light-emitting elements and the plurality of light-receiving elements are densely provided in one package, it is considered that leakage light or stray light from an adjacent light-emitting element, other than light emitted from one light-emitting element desired to be originally monitored, may also be incident on one light-receiving element.
When the leakage light or the like described above is incident on the light-receiving element, the light-receiving element cannot obtain a precise monitoring result. As a result, it may become difficult to control the intensity of the light emitted from the one light-emitting element so as to be constant.